It is known that certain chemical fluids, especially chlorofluorocarbons (hereinafter CFCs), destroy the ozone layer which serves to protect all life on the planet Earth from the effects of ultraviolet radiation from the Sun. As a consequence, CFCs have been phased out in the use of propellants for aerosol sprays. On the other hand, because CFCs are exceptionally good refrigerants, their use as refrigerant fluids has continued and it is expected will continue for many years both in refrigeration circuits and air conditioning circuits.
The patent literature contains many disclosures of systems for the recovery and/or recycling of refrigerants to prevent their escape into the atmosphere. Among these there may be briefly mentioned the Cain U.S. Pat. No. 4,261,178; Lofland U.S. Pat. No. 4,856,289; Lounis U.S. Pat. No. 4,862,699; Sparano U.S. Pat. No. 3,232,070; Merritt U.S. Pat. No. 4,903,499; and Proctor U.S. Pat. No. 4,909,042. Of these, Lofland '289 discloses the distilling off of CFCs leaving water behind, and further uses a drier with an absorptive medium such as activated charcoal to absorb any residual water. Lounis '699 mentions the use of a filter/dryer, as do other patents in this field including Staggs U.S. Pat. No. 4,539,817 and Taylor U.S. Pat. No. 4,646,527, as well as the Manz et al U.S. Pat. Nos. 4,768,347, 4,805,416 and 4,809,520.
Anderson U.S. Pat. No. 4,887,435 discloses a refrigeration cleaning and flushing system which uses a dehydrator filled with what is apparently a solid desiccant. Koser U.S. Pat. No. 4,285,206 also mentions the use of desiccants such as silica gel, activated aluminum oxide, barium oxide and phosphorous pentoxide. The patents to Margulefsky et al U.S. Pat. Nos. 4,480,446 and 4,554,792 disclose the use of filter elements of activated alumina, cellulose fibers or the like to remove moisture. Goddard 4,476,688 uses an acid purification filter-drier to remove moisture. The patents to Lower et al U.S. Pat. Nos. 4,364,236 and 4,441,330 mention the use of molecular sieve filters of activated alumina.
All of these prior systems for recycling and/or reclaiming of CFCs suffer from loss of filter efficiency over time and the need to frequently replace the water-removing filters.
The Rodda U.S. Pat. No. 4,856,290 appears to attempt to remove water by the use of oil to isolate the water in the system, after which the oil and water are drained away. Other systems, including the system of Lofland '289 mentioned above as well as Taylor '527, in part or in whole use distillation to separate CFCs from water. These systems suffer from undue complexity as do some of the filtering systems mentioned above. All of the prior systems, insofar as is known, suffer from the inability to reduce the moisture content of CFCs to below 20 ppm without great difficulty and below 10 ppm even if extra-ordinary care is taken.
The need for efficient reclamation and recycling of CFCs has recently become eve greater than previously, because of the recent passage of the Clean Air Act and similar legislation in various states. An excise tax has been imposed on certain refrigerants providing great economic incentive for recycling/reclamation. Some states are in the process of establishing laws to make refrigerant recovery and recycling/reclamation mandatory or to restrict refrigerant disposition to hazardous waste sites.
Production curtailments of certain refrigerants will inevitably result in higher prices for all refrigerants, and refrigerant recovery and recycling/reclamation will become increasingly important from an economic point of view as well as an environmental.
The Packo et al U.S. Pat. Nos. 4,237,172; 4,304,805; 4,331,722; 4,379,067; and 4,442,015 disclose the use of various types of organosilane compounds for sealing leaks in piping systems including air conditioning and refrigeration circuits, which organosilane compounds react with water at the situs of the leak to thereby seal such leak. These Packo et al U.S. patents are hereby incorporated by reference.
The Brown U.S. Pat. No. 3,912,651 discloses the use of acyloxy silanes in hydraulic and damping liquids based on end blocked polydimethylsiloxanes. The silane reacts with water in the polydimethyl siloxane fluid thereby preventing an accumulation of liquid water in the fluid system. The contents of said Brown U.S. Pat. No. 651 are hereby incorporated by reference.
The Packo et al U.S. Pat. No. 4,508,631 is directed to the incorporation of certain organosilane compounds in air conditioning and refrigeration circuits in order to sequester the moisture present in such circuits and thereby increase the life of the refrigeration circuits and so that corrosion leaks will not develop. Such Packo et al U.S. Pat. No. 4,508,631 is hereby incorporated by reference.